Interesting. I'm thinking a building you must donate money to get and keep a certain prize like IPH boost, or some sort of stat increase.

So to buy a building is 100'000 dollars and you get 10% building upgrade. But to keep the building you must donate 100,000 every 4 hours to keep it or upgrade it to level two which would be 350,000. If you don't donate within 4 hours the build goes back to level 1 or disappears.

This would be cool. Just a random idea

Any ways hopefully boost buildings don't suck